Hypertrophic Scar Fibroblasts Research Articles

MicroRNA-222 regulates proliferation and apoptosis of fibroblasts in hypertrophic scar via matrix metalloproteinase 1

Objective: To explore the effect of microRNA(miR)-222 on cell proliferation and apoptosis of fibroblasts in hypertrophic scar (HS) and the underlying mechanisms. Methods: The expression of miR-222 in the HS and the normal skin tissues was detected by real-time RT-PCR. The HS fibroblasts were transfected with miR-222 mimic and miR-222 inhibitor respectively. The cell viability was tested with MTT assay, cell cycle distribution and apoptosis were detected with flow cytometry and the expression levels of proliferation, apoptosis and cell cycle related proteins were determined with Western blot. Direct target of miR-222 was evaluated by dual-luciferase reporter assay. Results: miR-222 was significantly up-regulated in HS tissues compared with normal skin tissues(P<0.05). Overexpression of miR-222 enhanced the cell viability of HS fibroblasts; increased mRNA and protein expressions of proliferating cell nuclear antigen (PCNA), collagen alpha-1 (Ⅰ) chain (Col1A1) and collagen alpha-1 (Ⅲ) chain (Col3A1); increased cell population in S phase and protein expressions of cyclin D1, cyclin E1 and cyclin-dependent kinases 1 (CDK1); inhibited cell apoptosis and reduced protein expressions of caspase-3/9. Overexpression of MMP1 attenuated the effects of miR-222 on the cell viability and apoptosis in fibroblasts, reduced expression levels of PCNA, cyclin D1 and the expression of caspase-3 was increased. Conclusion: miR-222 enhances cell proliferation and inhibits cell apoptosis of HS fibroblasts through negative regulation of MMP1, which suggests that miR-222 and MMP1 might be used as novel biomarkers and targets in diagnostic and therapeutic approaches for HS.

Effect of recombinant human endostatin on hypertrophic scar fibroblast apoptosis in a rabbit ear model

Hypertrophic scar (HS) is a dermal fibroproliferative disorder characterized by the excessive proliferation of fibroblasts and is thought to result from a cellular imbalance caused by the increased growth and reduced apoptosis of hypertrophic scar fibroblasts (HSFs). Our recent study demonstrated that recombinant human endostatin (rhEndostatin) plays a key role in the inhibition of HSF proliferation in vitro, with a resulting decrease in dermal thickness and scar hypertrophy. However, the effect of this protein on HSF apoptosis is unknown. The present study was undertaken to directly examine the effect of rhEndostatin on HSF apoptosis in the rabbit ear model. Transmission electron microscopy and flow cytometry were used to investigate HSF apoptosis in scar tissues and cultured HSFs in vitro, respectively. The expression levels of the c-jun, c-fos, NF-κB, fas, caspase-3, and bcl-2 gene products in HSFs were quantified using real-time PCR and Western blotting assays. Our data reveal that rhEndostatin (2.5 or 5mg/ml) induces HSF apoptotic cell death in scar tissue. Additionally, HSFs treated with rhEndostatin (100mg/L) in vitro accumulated in early and late apoptosis and displayed significantly decreased expression of c-jun, c-fos, NF-κB, fas, caspase-3 and bcl-2. In sum, these results demonstrate that rhEndostatin induces HSF apoptosis, and this phenotypeis partially due to downregulation of NF-κB and bcl-2. These findings suggest that rhEndostatin may have an inhibitory effect on scar hypertrophy in vivo via HSF apoptotic induction and therefore has potential therapeutic use for the treatment of HS.

923 The effects of rose bengal on hypertrophic scar fibroblast cell viability and proliferation

923 The effects of rose bengal on hypertrophic scar fibroblast cell viability and proliferation

Pleiotropic FTY720 Is a Specific and Potent Therapy for Hypertrophic Scars

Hypertrophic scarring (HS) is a fibrotic skin condition characterized by aberrant fibroblast phenotypes and excessive deposition of extracellular matrix components. 2-Amino-2-[2-(4-octylphenyl)]-1, 3-propanediol hydrochloride (FTY720), an immunomodulator approved for treating multiple sclerosis, is reported to attenuate fibrosis in multiple disease models. Here we found that FTY720 could significantly attenuate the proliferation and fibrosis in HS fibroblasts (HSFs) and in an animal HS model. Upon treating HSFs or normal dermal fibroblasts with FTY720 at different concentrations for different time periods, we found that FTY720 presented a pleiotropic effect specifically on HSFs but not NFs, including reducing cell viability, arresting cell cycle progression at the G0/G1 phase, promoting apoptosis, inhibiting migration and contraction, and suppressing the expressions of α-smooth muscle actin, collagen I, and collagen III. Mechanistic studies showed that the antifibrotic activities of FTY720 were potentially mediated through sphingosine 1-phosphate receptor 5 to inhibit the protein kinase B/mTOR/p70S6K, but not the Smad, signaling pathway. The invitro actions of FTY720 also translated into a rabbit ear HS model, stimulating the healing of HS. These findings collectively suggest that FTY720 targets multiple phenotypes of HSFs and is a promising therapeutic agent for HS.

Inhibition of fibroblast histomorphology induced by sonodynamic therapy with hematoporphyrin monomethyl ether

Objective To investigate the mechanism of the effect of HMME-SDT on the proliferation of hypertrophic scar fibroblasts (Fb). Methods Fibroblast suspensions of rabbit ear with hypertrophic scar were divided into four groups: control group, ultrasound group, HMME group and HMME-SDT group. The survival of the fibroblast suspension of rabbit ear were determined by MTT assay method. The mitochondrial membrane potential, cellular reactive oxygen, the concentration changes of cellular calcium ion were also investigated by flow cytometry correspondingly. Nucleolar morphology was observed by 33258 nucleoli stain. Results There was significant difference between the SDT group and control, HMME and ultrasound groups at same time (P< 0.01). There were significant differences between the HMME-SDT group and HMME, ultrasound and control groups on cellular reactive oxygen, nucelus concentration and floccuent change as well as nuclear margination. Conclusions HMME-SDT can inhibit the proliferation of hypertrophic scar fibroblasts of rabbit ear significantly. Key words: Sonodynamic therapy; Hematoporphyrin monomethyl ether; Fibroblast

MicroRNA‑185 regulates transforming growth factor‑β1 and collagen‑1 in hypertrophic scar fibroblasts.

Transforming growth factor-β1 (TGF-β1) and collagen type I (Col-1) serve a critical role in the development and progression of hypertrophic scarring (HS). The present study hypothesized that a post-translational mechanism of microRNAs (miR) regulated the expression of TGF-β1 and Col-1 in HS fibroblasts (HSFBs). A collection of 20 HS tissues was compared with corresponding normal tissues from clinical patients, and the expression of miR-185 was measured. Using PicTar, TargetScan and miRBase databases, it was identified that miR-185 may be a regulator of TGF-β1 and Col-1 in humans. Based on these hypotheses, the expression of miR-185, TGF-β1 and Col-1 in HS tissues was investigated. The results demonstrated that the expression of miR-185 was markedly suppressed, and TGF-β1 and Col-1 levels were increased, in HS tissues. The expression levels of endogenous miR-185 negatively correlated with the TGF-β1 and Col-1 mRNA levels (Pearson's correlation coefficient r=−0.674, P<0.01 and r=−0.590, P<0.01, respectively). In vitro, miR-185 can regulate TGF-β1 and Col-1 through the predicted binding sites in its 3′-untranslated region. miR-185 had an effect on cell proliferation and apoptosis, thereby regulating HSFBs growth. In addition, miR-185 gain-of-function decreased TGF-β1 and Col-1 protein expression, and miR-185 loss-of-function increased TGF-β1 and Col-1 protein expression in HSFBs. In conclusion, overexpressed miR-185 could inhibit HSFBs growth, and the underlying mechanism was mediated, at least partly, through the suppression of TGF-β1 and Col-1 expression. However, above all, miR-185 might serve as a potential therapeutic approach for the treatment of HS.

MicroRNA expression signature and the therapeutic effect of the microRNA‑21 antagomir in hypertrophic scarring.

Hypertrophic scars (HS) area fibroproliferative disorder of the skin, which causes aesthetic and functional impairment. However, the molecular pathogenesis of this disease remains largely unknown and currently no efficient treatment exists. MicroRNAs (miRNAs) are involved in a variety of pathophysiological processes, however the role of miRNAs in HS development remains unclear. To investigate the miRNA expression signature of HS, microarray analysis was performed and 152 miRNAs were observed to be differentially expressed in HS tissue compared with normal skin tissues. Of the miRNAs identified, miRNA-21 (miR-21) was significantly increased in HS tissues and hypertrophic scar fibroblasts (HSFBs) as determined by reverse transcription-quantitative polymerase chain reaction analysis. It was also observed that, when miR-21 in HSFBs was blocked through use of an antagomir, the phenotype of fibrotic fibroblasts in vitro was reversed, as demonstrated by growth inhibition, induction of apoptosis and suppressed expression of fibrosis-associated genes collagen type I α 1 chain (COL1A1), COL1A2 and fibronectin. Furthermore, miR-21 antagomir administration significantly reduced the severity of HS formation and decreased collagen deposition in a rabbit ear HS model. The total scar area and scar elevation index were calculated and were demonstrated to be significantly decreased in the treatment group compared with control rabbits. These results indicated that the miR-21 antagomir has a therapeutic effect on HS and suggests that targeting miRNAs may be a successful and novel therapeutic strategy in the treatment of fibrotic diseases that are difficult to treat with existing methods.

Effects of severe hypoxia and low concentration of serum protein on the function of human hypertrophic scar fibroblasts

Objective: To simulate the environmental factors during the process of formation and evolution of hypertrophic scar, so as to explore the effects of moderate and severe hypoxia and low concentration of serum protein on the function of human hypertrophic scar fibroblasts (HSFs). Methods: Human HSFs were routinely cultured. Cells of the 3rd to the 6th passage were divided into 10.0% oxygen+ 10.0% fetal calf serum (FCS), 5.0% oxygen+ 5.0% FCS, and 0.5% oxygen+ 0.5% FCS groups according to the random number table. After being cultured with DMEM nutrient solution with no FCS for 24 h, the cells were cultured with the corresponding volume fraction of oxygen and FCS. Cell proliferation activity was determined with methyl-thiazole-tetrazolium assay (denoted as actual cell number). Content of total collagen was detected with Sirius red staining method (denoted as absorbance value). Protein expression levels of hypoxia-inducible factor 1α (HIF-1α), vascular endothelial growth factor (VEGF), transforming growth factor β1 (TGF-β1), B-cell lymphoma 2 (Bcl-2), and P53 were determined with Western blotting (denoted as ratio of gray value). Cell apoptosis rate was detected by in situ end labeling method. The sample numbers of each group in the above experiments were all 3. Data were processed with Kruskal-Wallis test and Dunnett test. Results: (1) Compared with 11 000±1 306 in 10.0% oxygen+ 10.0% FCS group, the cell proliferation activity was higher in 5.0% oxygen+ 5.0% FCS group (13 290±1 500, P<0.05), but lower in 0.5% oxygen+ 0.5% FCS group (6 999±765, P<0.05). (2) Compared with 0.039 6±0.004 2 in 10.0% oxygen+ 10.0% FCS group, the content of total collagen of cells was higher in 5.0% oxygen+ 5.0% FCS group (0.051 6±0.005 1, P<0.05), but lower in 0.5% oxygen+ 0.5% FCS group (0.015 6±0.002 4, P<0.05). (3) Compared with those in 10.0% oxygen+ 10.0% FCS group, the protein expression levels of HIF-1α, VEGF, TGF-β1, and Bcl-2 were increased (with P values below 0.05), with no obvious difference in protein expression level of P53 in 5.0% oxygen+ 5.0% FCS group (P>0.05), whereas the protein expression levels of HIF-1α, VEGF, TGF-β1, and Bcl-2 were decreased (with P values below 0.05), while the protein expression level of P53 was increased in 0.5% oxygen+ 0.5% FCS group (P<0.05). (4) Compared with (1.2±0.9)% in 10.0% oxygen+ 10.0% FCS group, the cell apoptosis rate in 5.0% oxygen+ 5.0% FCS group showed no significant difference [(2.6±0.9)%, P>0.05], while it was significantly increased in 0.5% oxygen+ 0.5% FCS group [(13.3±4.1)%, P<0.05]. Conclusions: Severe hypoxia and low concentration of serum protein can inhibit proliferation activity and production of total collagen of human HSFs and induce their apoptosis.

Lumican alleviates hypertrophic scarring by suppressing integrin-FAK signaling

Hypertrophic scarring (HS) is an overcompensation of wound healing that increases the risk of cosmetic disfigurement and functional impairment. No gold standard has been established for the treatment or prevention of HS. Our study aims to elucidate the expression and function of lumican in the pathogenesis of HS as well as the underlying mechanism involved in this procedure. An animal model of HS (rabbit ear) was established, and the Ad-lumican vectors were locally injected. Primary fibroblasts isolated from patients with hypertrophic burn scars were used in vitro. Histological and molecular changes in HS pathogenesis were evaluated. The results showed that lumican is significantly reduced in HS tissues and fibroblasts from HS patients as compared to normal skin or cells. Lumican levels were further suppressed in response to TGF-β stimulation. However, lumican upregulation effectively thinned the scar area and inhibited fibroblast proliferation and the cell cycle. Meanwhile, Ad-lumican administration suppressed the deposition of extracellular matrix, such as collagen and CTGF.Ad-lumican injected animals or fibroblasts presented comparable integrin α2β1 expression while greatly reduced phosphorylation of FAK compared to the negative control. Moreover, Ad-lumican administration largely enhanced the binding of lumican to integrin α2β1 and may thus inhibit the signaling propagation of collagen-integrin α2β1. Overall, the restoration of lumican levels contributed to suppressing the HS progression by inhibiting collagen-integrin α2β1-FAK signaling.

Inhibitory effect of recombinant human endostatin on the proliferation of hypertrophic scar fibroblasts in a rabbit ear model

Hypertrophic scar (HS) is a pathological scar that particularly occurs after traumatic injuries, surgical procedures and burning. Abnormal activation of hypertrophic scar fibroblasts (HSFs) intensifies fibrosis during wound healing. Our previous studies demonstrated that recombinant human endostatin (rhEndostatin) prevented synovial thickening in adjuvant arthritis (AA) rats via inhibition of proliferation and enhancement of apoptosis in synovial fibroblasts. However, the effect of this protein on HSF proliferation is not known. This study investigated the inhibitory effect of rhEndostatin on the proliferation of cultured HSFs in a rabbit ear model. MTT assay and flow cytometric detection were performed to investigate HSF proliferation and cell cycle progression, respectively. The expression levels of p53, p21, cyclinD1, cyclin-dependent kinase 4 (CDK4) and proliferating cell nuclear antigen (PCNA) in HSFs were detected using real-time PCR and Western blotting. Our data revealed that HSFs treated with rhEndostatin were significantly inhibited in a concentration-dependent manner with an IC50 value of 100mg/L. Also, rhEndostatin (100mg/L) primarily induced G0/G1 and partially G2/M cell cycle arrest of HSFs. There were significant decreases in the expression levels of p53, p27, CDK4, cyclinD1 and PCNA in HSFs treated with rhEndostatin. In conclusion, rhEndostatin inhibited HSF proliferation via G0/G1 and/or G2/M phase arrest of the cell cycle, which was partially due to the down-regulation of cyclinD1, CDK4 and PCNA. These findings suggest that rhEndostatin may reduce scar hypertrophy in vivo via inhibition of HSF proliferation and may be a novel agent for HS treatment.

Molecular mechanisms of gallic acid-induced growth inhibition, apoptosis, and necrosis in hypertrophic scar fibroblasts

AimsTo explore the effect and molecular mechanism of gallic acid (GA) on the cytostatic and cytotoxicity of hypertrophic scar fibroblasts (HSFs). Materials and methodsHSFs were treated with a serial dose of GA for indicated time. The cytostatic and cytotoxicity of GA were evaluated by microscopy, trypan blue exclusion assay and LDH releasing. The mechanisms of GA-induced cytostatic were examined by cell cycle distribution assay and the expression of cell cycle-relative protein. GA-elicited apoptosis were verified by TUNEL assay, mitochondria membrane potential, caspase activity and the expression of apoptosis-relative protein. GA-induced necrosis was confirmed by lysosome rupture using acridine orange stain. Various blockers, including intracellular calcium chelator; BAPTA-AM, IP3R blocker; 2-APB, calpain inhibitor, ALLM and ALLN were used to address the signaling cascade in GA-induced HSF necrosis. Key findingsGA-induced growth inhibition, apoptosis, and necrosis in HSFs depend on increasing dose. HSFs treated with GA at non-cytotoxic concentrations (50 to 75μM) significant increased both the S- and G2/M-phase HSFs population, and this event was accompanied with down-regulation of cyclin A, cyclin B, CDK1 and CDK2. Incubation of HSFs with 100–150μM of GA induced apoptosis through Bcl2/Bax-mitochondrial-dependent pathway. While the concentrations up to 200μM of GA that elicited necrosis via a calcium/calpain I/lysosome rupture signaling axis. Interestingly, GA at 200μM did not harm to keratinocyte. SignificanceThese results revealed that GA might have the potential to be developed as a treatment for patients with hypertrophic scar.

Gallic acid attenuates TGF-β1-stimulated collagen gel contraction via suppression of RhoA/Rho-kinase pathway in hypertrophic scar fibroblasts

AimsTo examine the effect and molecular mechanism of gallic acid (GA) on transforming growth factor-β1 (TGF-β1)-stimulated hypertrophic scar fibroblast (HSF) contraction. Materials and methodsA fibroblast-populated collagen lattice (FPCL) was developed to examine the effect of GA on TGF-β1-enhanced HSF contraction. The changes in crucial factors related to cell contraction including α-smooth muscle actin (α-SMA), F-actin, and the phosphorylation level of myosin light chain (MLC) were evaluated using western blot and immunostaining. The activation and expression of RhoA/ROCK after the TGF-β1 challenge and GA insult were evaluated using RhoA-G-LISA and RhoA-ELISA kit while the phosphorylation level of MYPT1 and the expression of ROCK1 and ROCK2 were examined by western blot, respectively. Key findingsGA significantly suppressed TGF-β1-stimulated HSF contraction in a dose- and time-dependent manner. Moreover, the TGF-β1-enhanced α-SMA expression, F-actin formation, and MLC phosphorylation were obviously attenuated by GA. TGF-β1 significantly stimulated RhoA activation but did not alter the expression of RhoA in the HSFs. However, both the activation and expression of RhoA decreased obviously with GA pretreatment followed by TGF-β1 stimulation. Furthermore, GA inhibited ROCK activity but did not affect its expression after TGF-β1 stimulation. SignificanceThese results suggest that GA exhibited the potential to prevent HSF contraction after TGF-β1 stimulation by down regulating the RhoA/ROCK signal cascade, followed by the inhibition of the expression of α-SMA, F-actin formation, and phosphorylation of MLC.

Influences of human dermis derived mesenchymal stem cells on α-SMA and DCN expressions of hypertrophic scars fibroblasts

To preliminarily explore the effects of human dermis derived mesenchymal stem cells (hDMSCs) on expressions of α-smooth muscle actin (α-SMA) and decorin (DCN) in hypertrophic scars fibroblasts (HSFB) at different periods,and to explore the feasibility of MSCs in prevention and treatment of HSFBs. hDMSCs were cultured with mechanical method combined with enzyme digestion.The cells of the third generation which were well grown were taken,and flow cytometry (FCM) was used to detect CD molecules in hDMSCs.Immunocytochemistry was used to detect cytokeratin 19 (CK19) and vimentin and identify the separated cells.The cells were differentiated into lipoblasts,chondroblasts and osteoblasts.According to the formation course of hypertrophic scar,the scar specimens were divided into 6-month,l-year,and 2-year group with three cases in each group.HSFBs from different groups were co-cultured with well-adherent hDMSCs of the third generation in non-contact transwell co-culture system for 21 days. And HSFBs from the corresponding groups were cultured in normal six-well plate as the controls.Real-time fluorescent-polymerase chain reaction (RT-PCR) and Western Blot were used to detect the expressions of mRNA and proteins of α-SMA and DCN in HSFBs from different groups. hDMSCs highly expressed the surface markers including CD73,CD105,CD44 and CD90,etc.,but did not express hematopoietic stem cell surface markers including CD 14,CD34 and CD45.They positively expressed vimentin but not CK19.The cells can be differentiated into lipoblasts,chondroblasts and osteoblasts,which was in line with the minimum identification standards of mesenchymal stem cells.For HSFB cultured in normal six-well plates,α-SMA mRNA and protein expressions of HSFB in the 6-month,1-year and 2-year groups were 198.20 ± 15.46/0.29 ± 0.070,175.24 ± 17.04/0.38 ± 0.110,and 125.73 ± 6.99/0.33 ±0.085,respectively;while DCN mRNA and protein expressions of HSFB in the corresponding groups were 61.30 ± 9.79/0.015 ± 0.003,70.89 ± 11.29/0.020 ± 0.007,and 77.31 ± 4.80/0.023 ± 0.003,respectively.For HSFB co-cultured with 5 × 104 hDMSCs, oα-SMA mRNA and protein expressions of HSFB in the 6-month,1-year and 2-year groups were 48.40 ± 6.42/ 0.100 ± 0.020,192.16 ± 11.37/0.110 ± 0.014,and 73.33 ± 6.29/0.110 ± 0.016,respectively;while DCN mRNA and protein expressions of HSFB in the corresponding groups were 156.92 ± 14.91/0.049 ±0.015,154.42 ± 18.17/0.033 ± 0.008,and 140.82 ± 7.32/0.030 ± 0.004,respectively.Compared with the control group(Cultured in normal six-well plates), mRNA and protein expressions of α-SMA in HSFBs were decreased after co-culture with 5 × 104 hDMSCs, mRNA and protein expressions of DCN were increased. Furthermore, it suggested that hypertrophic scar changed significantly in the early formation stage namely in the 6-month group. hDMSCs can down-regulate α-SMA mRNA and protein expressions of HSFBs and up-regulate mRNA and protein expressions of DCN in the in-vitro culture system.Those effects were particularly obvious on fibroblasts at the early formation of hyperplastic scar.Anti fibrosis role of hDMSCs is expected to be used in increasing the healing quality of the wound and in the prevention and treatment of pathological scars.

Fibroproliferative effect of microRNA-21 in hypertrophic scar derived fibroblasts

Hypertrophic scar (HS) is a fibroproliferative disorder caused by abnormal wound healing, which is characterized by excessive deposition of extracellular matrix (ECM) secreted by fibroblasts. We previous have found that expression of microRNA-21(miR-21) was increased in tissues and fibroblasts of HS. However, the underlying molecular mechanism remains to be further elucidated. In this study, we identified the miR-21 was a marker for the phenotype of HS fibroblasts, as anti-miR-21 reduced expression of fibrosis markers such as Col1A1, Col3A1, Fn and α-SMA in fibroblasts and overexpression of miR-21 promoted fibroproliferative expression in fibroblasts. Furthermore, we also found that miR-21 promoted TGF-β1 induced fibroproliferative expression by repressing Smad7 expression in vitro. In addition, the miR-21 inhibitor inhibited the growth of hypertrophic scar tissue in vivo (nude mice experimental model). These results indicated that miR-21 was a critical regulator for HS formation and TGF- β1/miR-21/Smad7 pathway could be a useful therapeutic target for the treatment of HS.

MicroRNA-143-3p inhibits hyperplastic scar formation by targeting connective tissue growth factor CTGF/CCN2 via the Akt/mTOR pathway.

Post-traumatic hypertrophic scar (HS) is a fibrotic disease with excessive extracellular matrix (ECM) production, which is a response to tissue injury by fibroblasts. Although emerging evidence has indicated that miRNA contributes to hypertrophic scarring, the role of miRNA in HS formation remains unclear. In this study, we found that miR-143-3p was markedly downregulated in HS tissues and fibroblasts (HSFs) using qRT-PCR. The expression of connective tissue growth factor (CTGF/CCN2) was upregulated both in HS tissues and HSFs, which is proposed to play a key role in ECM deposition in HS. The protein expression of collagen I (Col I), collagen III (Col III), and α-smooth muscle actin (α-SMA) was obviously inhibited after treatment with miR-143-3p in HSFs. The CCK-8 assay showed that miR-143-3p transfection reduced the proliferation ability of HSFs, and flow cytometry showed that either early or late apoptosis of HSFs was upregulated by miR-143-3p. In addition, the activity of caspase 3 and caspase 9 was increased after miR-143-3p transfection. On the contrary, the miR-143-3p inhibitor was demonstrated to increase cell proliferation and inhibit apoptosis of HSFs. Moreover, miR-143-3p targeted the 3'-UTR of CTGF and caused a significant decrease of CTGF. Western blot demonstrated that Akt/mTOR phosphorylation and the expression of CTGF, Col I, Col III, and α-SMA were inhibited by miR-143-3p, but increased by CTGF overexpression. In conclusion, we found that miR-143-3p inhibits hypertrophic scarring by regulating the proliferation and apoptosis of human HSFs, inhibiting ECM production-associated protein expression by targeting CTGF, and restraining the Akt/mTOR pathway.

Exposure to Varying Strain Magnitudes Influences the Conversion of Normal Skin Fibroblasts Into Hypertrophic Scar Cells.

Mechanical strain is a key contributor in the pathogenesis of hypertrophic scarring, whose optimal stretch magnitudes to initiate the differentiation of normal skin fibroblasts into aberrant fibroblasts phenotype remains largely unresolved. Influence of varying cyclic strain magnitudes on cultured human normal skin fibroblasts and its transformation into hypertrophic scar fibroblast-like phenotype is investigated in this study. Cultured fibroblasts isolated from hypertrophic scar and normal skin tissue were subjected to cyclic mechanical stretching under individual 10%, 15%, and 20% strain magnitudes at a frequency of 0.1 Hz for 24 hours. Stretched normal skin fibroblasts demonstrated significantly increased rates of cell proliferation, and also apparently oriented away nearly perpendicular to the applied stretching direction. Interestingly, the applied 10% strains magnitude resulted in a markedly enhanced cell proliferative ability compared with that of 20% strain magnitude. Parameters involving the mechanotransduction signaling, such as integrin β1 and P130Cas, were significantly improved at both mRNA and protein levels in the stretched normal skin fibroblasts, which was demonstrated in a negative magnitude-dependent manner. In addition, 10% strains magnitude triggered the highest expression levels of growth factor TGF-β1 and collagen matrix in stretched normal skin fibroblasts. Collectively, these results indicate that the 10% stretching magnitude, of the 3 strain magnitudes studied, is most effective for triggering the optimal mechanotransduction effects and biological responses inside cultured skin fibroblasts. The demonstrable conversion of normal skin fibroblasts into hypertrophic scar fibroblasts was also observed when 10% stretching magnitude was applied to cultured fibroblasts in vitro.

Cryptotanshinone downregulates the profibrotic activities of hypertrophic scar fibroblasts and accelerates wound healing: A potential therapy for the reduction of skin scarring.

Hypertrophic scar (HS) is a skin fibrotic disease that causes major clinically problematic symptoms. Cryptotanshinone (CT) is an important ingredient of Danshen (Salvia miltiorrhiza Bunge extract) that has been used to treat cardio-cerebral vascular diseases. Its clinical efficacy in HS remains unclear. To investigate whether CT can inhibit HS fibrosis, HS-derived fibroblastic cells (HSFs) were established and treated with or without CT. Type-collagen-I (Col1), type-collagen-III (Col3) and α-smooth muscle actin (α-SMA) expression were measured by western blot and real-time quantitative polymerase chain reaction. HSFs migration and contraction were assessed with the scratch assay and the fibroblast-populated collagen lattice (FPCL) contraction assay, respectively. Wound healing in CT-treated Balb/c mice was assessed by immunohistochemical analysis of collagen expression and Masson's trichrome staining analysis of collagen deposition. CT treatment of HSFs down-regulated Col1, Col3 and α-SMA mRNA and protein expression, HSFs migration, and HSFs contraction, and improved FPCL architecture. In mice, CT treatment accelerated wound healing: the scar margins were narrow and there was less collagen deposition in the regenerated tissue. Thus, CT promotes wound healing and decreases excessive deposition of extracellular matrix components. CT may help to prevent and reduce scarring.

Bone marrow derived mesenchymal stem cells inhibit the proliferative and profibrotic phenotype of hypertrophic scar fibroblasts and keloid fibroblasts through paracrine signaling

BackgroundHypertrophic scars and keloids, characterized by over-proliferation of fibroblasts and aberrant formation of the extracellular matrix (ECM), are considered fibrotic diseases. Accumulating evidence indicates that mesenchymal stem cells (MSCs) promote scar-free wound healing and inhibit fibrotic tissue formation, making them a potentially effective therapeutic treatment for hypertrophic scars and keloids. ObjectiveTo investigate the paracrine effects of bone marrow derived MSCs (BMSCs) on the biological behavior of hypertrophic scar fibroblasts (HSFs) and keloid fibroblasts (KFs). MethodsProliferative and profibrotic phenotype changes of the fibroblasts were analyzed by immunofluorescence staining, in-cell western blot, and real-time PCR. ResultsBMSC-conditioned medium inhibited HSF and KF proliferation and migration, but did not induce apoptosis. Interestingly, normal skin fibroblast-conditioned medium exhibited no inhibitory effects on HSF or KF proliferation and migration. Furthermore, BMSC-conditioned medium significantly decreased expression of profibrotic genes, including connective tissue growth factor, plasminogen activator inhibitor-1, transforming growth factor-β1, and transforming growth factor-β2, in HSFs and KFs at both transcriptional and translational levels. In contrast, the expression of antifibrotic genes, such as transforming growth factor-β3 and decorin, was substantially enhanced under the same culture conditions. Finally, we observed that BMSC-conditioned medium suppressed the ECM synthesis in HSFs and KFs, as indicated by decreased expression of collagen I and fibronectin and low levels of hydroxyproline in cell culture supernatant. ConclusionThese findings suggest that BMSCs attenuate the proliferative and profibrotic phenotype associated with HSFs and KFs and inhibit ECM synthesis through a paracrine signaling mechanism.

IL10 inhibits starvation-induced autophagy in hypertrophic scar fibroblasts via cross talk between the IL10-IL10R-STAT3 and IL10-AKT-mTOR pathways.

Hypertrophic scar (HS) is a serious skin fibrotic disease characterized by excessive hypercellularity and extracellular matrix (ECM) component deposition. Autophagy is a tightly regulated physiological process essential for cellular maintenance, differentiation, development, and homeostasis. Previous studies show that IL10 has potential therapeutic benefits in terms of preventing and reducing HS formation. However, no studies have examined IL10-mediated autophagy during the pathological process of HS formation. Here, we examined the effect of IL10 on starvation-induced autophagy and investigated the molecular mechanism underlying IL10-mediated inhibition of autophagy in HS-derived fibroblasts (HSFs) under starvation conditions. Immunostaining and PCR analysis revealed that a specific component of the IL10 receptor, IL10 alpha-chain (IL10Rα), is expressed in HSFs. Transmission electron microscopy and western blot analysis revealed that IL10 inhibited starvation-induced autophagy and induced the expression of p-AKT and p-STAT3 in HSFs in a dose-dependent manner. Blocking IL10R, p-AKT, p-mTOR, and p-STAT3 using specific inhibitors (IL10RB, LY294002, rapamycin, and cryptotanshinone, respectively) showed that IL10 inhibited autophagy via IL10Rα-mediated activation of STAT3 (the IL10R-STAT3 pathway) and by directly activating the AKT-mTOR pathway. Notably, these results suggest that IL10-mediated inhibition of autophagy is facilitated by the cross talk between STAT3, AKT, and mTOR; in other words, the IL10-IL10R-STAT3 and IL10-AKT-mTOR pathways. Finally, the results also indicate that mTOR-p70S6K is the molecule upon which these two pathways converge to induce IL10-mediated inhibition of autophagy in starved HSFs. In summary, the findings reported herein shed light on the molecular mechanism underlying IL10-mediated inhibition of autophagy and suggest that IL10 is a potential therapeutic agent for the treatment of HS.

Galangin inhibits hypertrophic scar formation via ALK5/Smad2/3 signaling pathway.

Hypertrophic scar (HS) is characterized by excessive fibrosis associated with aberrant function of fibroblasts. Currently, no satisfactory drug has been developed to treat the disease. Here we found that a flavonoid natural product, galangin, could significantly attenuate hypertrophic scar formation in a mechanical load-induced mouse model. Both in vivo and in vitro studies demonstrated that galangin remarkably inhibited collagen production, proliferation, and activation of fibroblasts. Besides, galangin suppressed the contractile ability of hypertrophic scar fibroblasts. Further Western blot analysis revealed that galangin dose-dependently down-regulated Smad2 and Smad3 phosphorylation. Such bioactivity of galangin resulted from its selective targeting to the activin receptor-like kinase 5 (ALK5) was demonstrated by ALK5 knockdown and over-expression experiments. Taken together, this compound could simultaneously inhibit both the accumulation of collagen and abnormal activation/proliferation of fibroblasts, which were the two pivotal factors for hypertrophic scar formation, thus suggesting that galangin serves as a potential agent for treatment of HS or other fibroproliferative disorders.